BANGKOK — Protesters in Thailand forced the closure of several government ministries today and vowed to take control of state offices nationwide in a bid to oust Prime Minister Yingluck Shinawatra, escalating the biggest challenge she has faced since taking office.

Police issued an arrest warrant for protest leader Suthep Thaugsuban, a former opposition lawmaker, who led the storming of the Finance Ministry a day earlier. But police said he would not be arrested at the rally as part of a pledge to avoid clashes with protesters.

Protesters say they want Yingluck, who took office in 2011, to step down amid claims her government is controlled by her brother, former Prime Minister Thaksin Shinawatra, who was ousted in a military coup in 2006.

Thaksin has lived in self-imposed exile for the past five years to avoid a two-year prison sentence on a corruption conviction.

Thousands of protesters fanned out to new targets in Bangkok today, emboldened by their takeover of the Finance Ministry, where Suthep and hundreds of protesters camped overnight. The transport, agriculture and tourism ministries were also closed today because of their proximity to protests.

Demonstrators surrounded the Interior Ministry and then cut electricity and water to pressure people inside to leave. Security personnel locked themselves behind the ministry’s gates, with employees still inside.

On Sunday, more than 100,000 demonstrators took to Bangkok’s streets, uniting against what they call the “Thaksin regime.”

What started a month ago as a campaign against a political amnesty bill has morphed into a wider anti-government movement. Protest leaders now say their ultimate goal is to uproot the Shinawatra network from Thai politics, with no explanation of what that means.

The occupation of the ministry offices has raised fears of violence and worries that Thailand is entering a new period of political instability. They also recall previous protests against Thaksin and his allies in 2008, when demonstrators occupied and shut down the prime minister’s offices for three months.

The main protest group appeared to have converted the Finance Ministry into its headquarters today, and declared today a “rest day,” as protesters erected tents in the parking lot.

“Tomorrow there will be a nationwide movement,” Akanat Promphan, a protest spokesman, told reporters inside the emptied ministry. He said the aim is to paralyze government operations by seizing offices and state agencies so they cannot be “used as a mechanism for the Thaksin regime.”

Separately on Tuesday, the opposition Democrat Party, which is spearheading the protests, launched a parliamentary no-confidence debate against Yingluck. The vote has no chance of unseating Yingluck as her ruling Pheu Thai party controls the House of Representatives.

Yingluck called for calm and offered to negotiate with protest leaders.

“If we can talk, I believe the country will return to normal,” she said.

Yingluck has vowed not to use violence to stop the protests but expanded special security laws late Monday to cover the entire capital. The Internal Security Act was already in place for three districts of Bangkok since August, when there were early signs of political unrest. It authorizes officials to impose curfews, seal off roads, restrict access to buildings and ban the use of electronic devices in designated areas.